No agreement from me. 17-18 year old players are not the same as 19-20 year old players. All thing being equal, a 17 year old is quite different physically and mentally than a 20 year old player, all your howling notwithstanding.
Bagley is 1.5 years younger and Ayton 1 year younger than Preston and both are dominating. DeSousa is older than Bagley and about the same age as Ayton. Azubuike is younger than all of them and doing fine at KU. Preston has been with team since the Summer and he is as fit as any of the other players. DeSousa attended an elite basketball prep school where preparing players for the next level is Job One and both faced top competition before joining KU. There is no reason why Preston and DeSousa could not compete in Division I; familiarity with KU's playbook will be the primary limitation for DeSousa and less so for Preston.